Continuous bake oven



NOV- 18, 1947- T. J. sTEHENs 1 2,431,207

CONTINUOUS BAKE OVEN Filed Nrov".` 25, 1942 i5 Sheets-Sheet 1 NV- 18, 1947. 12J. STEPHENS 2,431,207

' coNTmuou BAKE ovEN Filed Nov. 25. 1942 :s shams-sheet 2 fr cz- E- 'EX/1 ATTORNEY Patented Nov. 18, 194'] CONTINUOUS BAKE OVEN Thomas J. Stephens, New York, N. Y., assignor of, one-half to Charlotte von Glahn Seltman Application November 25, 1942, Serial No. 466,958

` (c1. lov-51) 5 Claims. 1

This invention relates to bakers ovens and particularly to the continuous type of such ovens in which articles to be bakedare introduced at one end of the baking chamber and their baking completed during their transit to the other end thereof.

An object of the invention is to provide means for and method of distributive heat application .to articles in transit through the oven which is adaptable of adjustment for establishment and maintenance of a xed set of heating conditions in all parts of the baking chamber, which conditions are adaptable for properly completing the baking of a specific type of article during its transit through the oven; and which conditions can be readily readjusted to meet the requirements for baking other articles, having diiTerent characteristics from the first.

I accomplish the object of lmy invention by means of certain steps which are carried out in an apparatus which is illustratively exemplified v in the accompanying drawings, in which Figure 1 is a substantially longitudinal sectional view of a portion of my improved bake oven;

Figure 2 is a substantially transverse sectional view taken on lines 2-2 of Figure 1;

Figure 3 is a sectional view taken on lines 3--3 of Figure 4; and

Figure 4 is a substantially transverse sectional view taken on lines 4--4 of Figure 3.

The present invention comprises an oven A having two longitudinal side walls I associated with a roof I I in such manner as to enclose a rectangular chamber, At a distance of approximately 30 to 48 inches above the iioor I4 a lateral partition or hearth I5 is disposed and appropriately supported to divide the said rectangular chamber, enclosed by the side walls I0 and the roof II, into an upper compartment C and a lower compartment D, The said transverse partition I5 is constructed in a manner and of materials to constitute a xed radiant hearth. The compartment D below the xed hearth I5 is subdivided into a sequential series of longitudinal compartments by a corresponding series of upright partitions I6 extending transversely from wall to wall; said vertical partitions I6 being impervious to the passage of gases therethrough. Each such lower longitudinal compartment is, preferably, subdivided by two equally spaced secondary upright partitions I1 into one primary and two secondary heat receiving chambersD' and D2, respectively. Preferably the primary heat receiving chamber D' is disposed midway 2 between the two corresponding secondary heat receiving chambers D2 and divided therefrom by the two secondary partitions I1. The secondary partitions I1 are provided with openings I8 communicating between the primary heat receiving chamber D and the secondary heat receiving chambers D2; said openings I8 comprising now ways through which gases may pass from the primary chamber D into the secondary chambers D2. The said vertical partitions I6 and I1 are carried upon longitudinal beams I9 having their ends supported by elements 20 of the side walls I0; said longitudinal beams being elevated above the floor to provide space therebeneath for the passage of the lower strand of an endless carrier 2l which passes at each endof the oven over a pulley (not shown), the upper run of the carrier traversing the baking chamber C for conveyance of the articles to be baked. The lowex confines of said heat receiving chambers may be metal plates I4 supported at their respective sides by the transverse members I9, see Fig. 1, thus being disposed in such relation to the lower run of the conveyor 2| as to impart heat thereto by radiation. The upper run of said carrier is disposed immediately above the fixed hearth I5 and is supported on a series of rollers 23, one of which is disposed over each impervious vertical partition I6. Each of said rollers is rotatably mounted on a shaft 24, each end of which is fixed in a gib 24'. Each gib 24 is slidably mounted to move vertically in guide bars 25, the gib being provided with an upright threaded rod 26, which extends upright through the roof of the oven into engagement with an axially threaded hand wheel 21, by means of which each roller 23 is elevated or lowered, as desired.

Each roller 23 comprises a length of seamless tube at least as long as the band or carrier 2l is wide and is iltted at each end with a graphite lled oilless bearing 28 which, after the ends of the tube have been counter-bored, is pressed from one to two inches into the counter-bore. The bearings 28 are mounted on the fixed shaft 24 which is disposed at right angles to the central line of movement of the band. The roller is positioned on the shaft by steel collars 29 which extend into the counter-bore and terminate slightly short of the bearings 28, thus providing a slight space to compensate unequal expansion when the rise in temperature of the roller is more rapid than. that of the protected shaft 24. Before assembly of the roller on the shaft, a quantity of powdered graphite 30 is placed in the roller and is confined between the two bearings. The graphite is intended to gradually and very slowly nd its way through the bearings 28, thus lubricating the bearings as well as the faces of the shaft collars 29 which, being iixed to the shaft 24, function, to a slight degree, as thrust bearings. The extensions of thewalls of the-roller over the inner end of the shaft collars 29 .prevent foreign matter reaching surfaces where attrition would be produced.

At an appropriate elevation above the upper strand of the carrier 2| there is a second transverse partition 3| to form the ceiling of the baking chamber; the said ceiling comprising metal plates which are perforated in a manner to facilitate the distributive flow of gases therethrough. The ceiling plates 3l are carried upon transverse beams 32, the ends of which are supported by elements 33 of the side walls I0 of the oven A. Each beam 32 comprises two angle bars united in parallel spaced relation to each other to form a flow way between their upright legs,

the lateral legs thereof extending outwardly to- -form a support for the perforated ceiling plates 3|. At an elevation of from 4 to 8 inches above the ceiling plates 3| roof supporting plates 34 are disposed. The roof supporting plates 34 are carried upon transverse beams 35, the ends of which are supported by elements 36 of the side walls I0. The transverse roof beams 35 are similar in construction and purpose to the ceiling beams 32 except that the space between their upright legs is somewhat greater. A rectangular duct 3l is disposed outside of the upright legs of each ceiling beam 32 and extends upright to fit between the upright legs df the corresponding roof beams 35. A duct 38 fits over the outside \of the upright legs of each' roof beam 35 and extends upright through the roof into communication with a longitudinal manifold exhaust duct 39. The construction just described provides a distributive vent for the baking chamber.

It will be seen that a chamber C is formed between the ceiling plates 3l and the roof plates 34., A series of ducts 40- of appropriate carrying capacity conveys the gases, and are preferably of arcuate form, each duct being disposed in each side wall Ill f the oven in a position to provide a flow way for gases from each end of each secondary heat receiving chamber D2 into the corresponding chamber C' formed between the ceiling of the baking chamber and the roof of the oven. By this arrangement heat laden gases which are either introducedby'pressure into a primary heat receiving chamber D', or which are generated by combustion therein, will be caused by vaction of a chimney 4|, or by an induced draft, to flow from the primary heat receiving chamber D' through the openings I3 in the secondary partitions I1 into the secondary heat receiving chambers D2, thence through the arcuate wall ducts 40 to the chamber C between the roofvplate 34 and the ceiling plate 3l. The same influence will cause the heat laden gases to be forced downwardly through the perforations of the ceiling plates 3| to `be distributed upon the products being borne through the baking chamber on the carrier 2|. Spent gases and vapor emitted by the baking product will be withdrawn from the baking chamber through transverse ducts 3l and 38 of the ceiling and roof beams into the manifold exhaust duct 33.

The under side of the articles being baked receive heat through radiation from the fixed hearth I5 beneath the carrier 2|.

The heat vehicle is introduced into the priand divided therefrom by mary heat receiving chambers' D ings 42 in the side walls Il. as Figures 1 and 2.

. In the arrangement described the temperature of the fixed hearth I5 will be maintained at approximately the initial temperature of the gases in the heat receiving chambers and the rate of transmissionof heat by radiation from the xed hearth to said articles will be inversely proportional to the distance between the hearth and said articles; likewise the rate of heat transfer from the ceiling to said articles will be on a similar ratio. Accordingly, by adjusting the elevational path of the carrier 2l between the hearth I6 and the ceiling 3| the proper or desired proportion of top heat and bottom heat can be determined and thereafter maintained I claim:

1. In a bake oven comprising a baking chamber and a longitudinally movable carrier traversing said baking chamber, the combination of a plurality of horizontally disposed perforated plates arranged below and spaced from the roof of the oven to form the ceiling of said baking chamber, vertical'partitions between said perforated plates extending to the roof of the oven to subdivide the space between said plates and roof into a plurality of upper chambers. a fixed hearth forming the bottom of said baking chamber, a longitudinally disposed series of transverse heat receiving chambers arranged beneath the baking chamber said fixed hearth, two transverse baille walls in each heat receiving chamber. said baille walls extending across the full width and height of said receiving chambers so as to divide each of said chambers into a central, primary heat receiving chamber and two secondary heat receiving chambers, each of said baille walls being provided with distributed openings therethrough to allow the passage of heated gases from the primary chamber into the respective secondary chamber, an upwardly extending conduit disposed at one end of each secondary heat receiving chamber, the lower ends of said conduits communicating respectively with the secondary heat receiving chambers and the upper ends thereof communicating with the respective upper chambers, and a series of transverse vent outlets, respectively disposed intermediately of said perforated plates, said vent outlets extendlng from communication with the baking chamber through the roof of the oven to discharge spent gases.

2. A roller support for a band conveyor comprising a length of seamless tube having a bearing bushing concentrically disposed therewithin at each of its respective ends, a shaft passing through said bearings and fixed against rotation, said tube and said shaft being of such relative diameters as to provide an annular reservoir within said tube, said reservoir being confined at its respective ends by said bearing bushings, a collar fixed to said shaft adjacent the respective outer face of each of said 4bearing bushings and a quantity of powdered lubricant carried within said reservoir to be gradually distributed into said bearings by the functional rotation of said tube about said shaft.

3. A roller support, as claimed in claim 2, in which said shaft isengaged at its respective ends by crossheads slidably mounted upon vertical guides and means in connection with said cross heads for adjustment of their respective positions upon said guides.

'4. An oven, comprising an elongated housing through openillustrated in having a horizontal baking chamber extending throughout its upper part, means for conveying articles to be baked through said baking chamber. a longitudinally disposed series of transverse heat receiving chambers arranged below said baking chamber and having their upper confines constituted to transfer heat outwardly therefrom, each of said heat receiving chambers having two transverse baille walls extending from bottom to top thereof, and dividing said; chamber into a central primary heat receiving chamber and two secondary heat receiving chambers, each of said baille walls being provided with distributed openings therethrough to allow the passage of heat laden gases from the primary chambers into the respective secondary chambers, and means for ,causing heat laden gases to flow from said sec-4 ondary heat receiving chambers upwardly into respective zones adjacently above said baking y chamber and thence distributively downwardly into said baking chamber and upon the upper surfaces of articles being conveyed therethrough.

5. In an oven having an endless conveyor extending therethrough, a rollery for 'support for said conveyor comprising a tube having a bushing fixed within each of its respective ends, each of said bushings being concentrically bored through, to forma bearing, a shaft passing through said bearings and fixed against rotation, a collar fixed to said shaft adjacent the respective outer face of each of said bearings, the respective outer ends of said tube overhanging a portion of each of' lll a said collars, the diameter of said tube being sumciently greater than the diameter of said shaft to form an annular reservoir between its inner wall and the surface of said shaft, said reservoir Ebeing conned, except for tolerance in said bearings, at its ends by said bushings, and a quantity of powdered lubricant carried in said reservoir to be gradually distributed into said bearings by the functional rotation of said tube about said fixed shaft.

' THUS. J. STEPHENS.

` REFERENCES CITED The following references are of record in the 

